African Bullfrog

(Pyxicephalus adspersus)

Facts

IUCN LEAST CONCERN (LC)

Facts about this animal

It is the largest amphibian found in southern Africa. Males can reach a snout-vent length of 24,5 cm and a mass of 1.4 kg. Males are olive in color, with yellow to orange on the throat region. Females are olive to light brown with cream to white throat areas. Both sexes have ridges running laterally on the dorsal surface. They have a spade like metatarsal tubercle on each hind foot to aid in digging.

During the dry season the frogs live underground. Breeding starts after heavy rain (initiated by 65 mm of rain over the previous day or two). They breed in shallow, temporary waterbodies, in pools, pans and ditches. Eggs are laid in the shallow edge of the pond, but fertilization takes place above water level. As many as 4000 eggs may be released. The males exhibit parental care. They watch over and defend the eggs which hatch in two days (they have been known to jump at things they regard to be a threat). After hatching, after two days, the tadpoles will feed on each other, as well as on small fish and invertebrates. Defending males will continue to watch over the tadpoles which will metamorphose within three weeks. During times when the pool nears dessication, the male will dig a channel between his offspring and the larger body of water. This parental care comes with a price, however, as the male will consume many of the tadpoles while he is defending them.

African bullfrogs consume nearly any animal that can be overpowered and can fit in their huge mouths. Cannibalism is a common occurrence beginning the moment they metamorphose. Other prey items include invertebrates, other species of frogs, reptiles, small mammals, and even small birds.

The tongue is folded over inside the mouth. To capture a potential meal, the frog will drop its lower jaw with considerable force, causing the tongue to flip over and out of the animal's mouth, seizing the prey. They can live up to 40 years.

Did you know?
Certain areas of their range can be completely dry for years at a time, and can reach surface temperatures over 38 degrees C, and drop to below freezing during the winter. Protected in an underground estivation chamber, the frogs wait it out until more suitable conditions occur. In fact, the majority of their lives are spent estivating underground. They slough off several layers of their skin's epidermal cells which form a tough cocoon, which prevents the evaporation of body fluids. Most of their bodily functions slow or shut down all together. They absorb water stored in their bladder. This period of dormancy may last a year or more. When the rainy season begins, they occupy temporary floodplains and rapidly drying puddles scattered around the African countryside.Males have two breeding strategies, depending on their age: Younger males congregate in a small area, perhaps only 1 or 2 square meters of shallow water. The larger males occupy the center of these breeding arenas or leks and attempt to chase off other males. In fact they fight, causing injury and even killing one another. The dominant male attempt to prevent other males from participating in breeding. A female approaches the group of males by swimming along at the surface until she is within a few meters of the group. Then the female dives to avoid the smaller males and surfaces in the defended area of a larger male in the middle of the group. She is soon grasped by one of the larger males, and mating ensures. Most of the females are mated by the dominant male in his territory.

Distribution

As one of the most adaptable amphibians on earth, Pyxicephalus adspersus can tolerate some of the harshest environments in Africa. It occurs in drier savannas in large pans that fill with water during rains. It has been found from the Kalihari desert, to the high veld domains between 1200 and 1500 m above sea level.

Wild population

It has a wide distribution, is tolerant of a broad range of habitats and has a presumed large population, However advancing civilization has driven it near extinction in certain parts of its range. They are eaten by humans, and have also been collected for the commercial pet trade.